Risk factors associated with congenital malaria in Enugu, South Eastern Nigeria

There is paucity of data on the risk factors associated with congenital malaria in Nigeria. This study assessed the risk factors for congenital malaria in a population of neonates delivered at the University of Nigeria Teaching Hospital, Enugu, South Eastern Nigeria. It was a prospective cross-sectional study of neonates who were delivered in the institution from 2 April 2003 to 15 April 2004 as well as their mothers. Thick and thin blood films were made from maternal, baby and cord blood as well as the placenta for each mother/baby pair to determine malaria parasite density counts and for species identification. The maternal samples were obtained as soon as labour was confirmed while the cord and baby's blood as well as placental smears were taken within 1 h of delivery. Data analysis was by means of descriptive and inferential statistics as well as univariate and multivariate logistic regression at the 95% confidence level using the statistical software SPSS for Windows Version 10. A total of 658 mother/baby pairs were recruited into the study within the 13-month period. Out of this number, 625 mother/baby pairs completed the study and their data were subsequently analysed. A total of 356 (56.96%) mothers and 203 (32.48%) babies were smear positive for Plasmodium falciparum. On univariate logistic regression with presence or absence of the congenital malaria as the dependent variable, six out of the 13 putative risk factors tested were statistically significant. These were low compared with higher socioeconomic classes (OR = 1.41, 95% CI = 1.18 - 1.69, p = 0.00); low compared with normal birth weight (OR = 2.14, 95% CI = 1.39 - 3.30, p = 0.001); positive placental malaria parasitaemia (OR = 6.29, 95% CI, 4.73 - 8.37, p = 0.000), positive maternal blood malaria parasitaemia (OR = 5.04, 95% CI = 3.74 - 6.78, p = 0.000), positive cord blood malaria parasitaemia (OR = 26.87, 95% = 15.79 - 45.74, p = 0.000) and parity of 0 - 1 compared with other parities (OR = 1.31, 95% CI = 1.11 - 1.55, p = 0.002). On multivariate logistic regression, three of the six factors that were significant on univariate logistic regression remained significant. These were: positive placental malaria parasitaemia (OR = 2.55, 95% CI = 1.45 - 4.47, p = 0.001); positive cord malaria parasitaemia (OR = 18.90, 95% CI = 10.68 - 33.46, p = 0.000 and parity of 0 - 1 compared with other parities (OR = 1.66, 95% CI = 1.09 - 2.52, p = 0.02). It was concluded that the risk factors for congenital malaria identified in this study emphasise the need for effective preventive and curative treatment of malaria not only during pregnancy but also during delivery in malaria endemic areas. Additionally, congenital malaria should now rank high among the list of differential diagnosis of fever in the newborn in such endemic areas.